Russian VVER-1000 reactors

Basic theses

Traditional Russian technologies of VVER-1000 reactors

For construction of nuclear power plants Atomstroyexport traditionally uses the light water reactor installations of VVER type, which are considered as one of the most reliable and safe in the world. Efficiency of VVER reactors has been proved by their successful operation  more than 1000 of trouble-free reactor-years. By the "price-quality" characteristics VVER-1000 design is one of the most preferable in comparison with all other used reactors. The basis of NPP safety provision based on VVER-1000 design (NPP-91/99, NPP-92) is an incorporated principle of defense in depth  application of the system of barriers on a path of propagation of ionizing radiation and radioactive substances into an environment and the system of engineering and organizational measures on protection of the barriers and preservation of their efficiency, and also direct protection of the population.

The power units with VVER-1000 reactors are operated and constructed in seven countries of the world (Russia, Ukraine, Bulgaria, Czechia, China, India, Iran). The NPP-92 design of this power unit is evolutionally developing and has presently undergone examination on compliance to all safety and reliability requirements adopted for NPP in the European Union (EUR). All best technologies of the state-of-the art nuclear power engineering were applied and realized in the current variant of the power unit design.

VVER-1000 - safe reactor

Water-cooled water-moderated power reactors (VVER) belong to the most widespread type of pressurized water reactors. Nowadays worldwide 267 such reactors are operated, 53 of them belong to VVER type.

The highest degree of reliability is a basic characteristic of VVER-1000 reactors.

These reactors incorporate the most advanced approaches to safety provision based on the principle of defense in depth and assuming several sequentially responding safety levels. The basic safety level of the system is preventive. The practical impossibility to have accidents at this level is reached due to reliability of the engineering design solutions, quality assurance of the applied equipment, civil and erection works and attraction of the competent and highly skilled personnel to performance of the works. If in case of unforeseen situations one of the protection levels fails to develop refuses, another one will immediately respond to prevent propagation of an accident. In case all these safety barriers fail, there is one more additional safety level, at which the certain safety systems are automatically activated, when even the most insignificant NPP operation parameters (temperature, pressure, capacity and others) start to exceed the set parameters. It is the so-called passive safety system, i.e. not demanding intervention of operators and power supply from external sources and guaranteeing, if necessary, reliable reactor shutdown.

Besides the reactor is provided with the double containment having a ventilated intershell gap and preventing release of radioactive substances into an environment, as well as upgrades.

The reactor containment is a leak-tight structure out of pre-stressed concrete more than one meter thick lined with steel inside. Such containment is capable to sustain the most maximal external loads right up to a direct aircraft crash. It includes the cooling systems and filters for prevention of releases of radioactive substances into an environment.

High reliability of these safety systems is provided by their redundancy, physical separation and principle of diversity.

Development of stage-by-stage quality assurance programs under a project is carried out prior to the beginning of any stage work  designing, manufacturing, construction, NPP operation. All works are regulated by the standards of Russia, IAEA, and requirements of the countries-customers.

Evolution of Russian VVER technologies

The analogue of foreign reactors of PWR type, i.e. a pressurized water-cooled water-moderated reactor (VVER), is a basis for the program of development of nuclear industry of Russia and for expansion of export of the Russian nuclear technologies. During the entire history of reactor construction the USSR and Russia constructed more than 50 nuclear power units of VVER type Р in Russia, Ukraine, Czechia, Slovakia, Hungary, Germany, Finland. At different stages there are VVER-based NPP construction projects in Russia, China, India, Iran, and Bulgaria. The NPP capacity line extends from first serial designs of VVER-440 up to the state-of-the art VVER-1000, VVER 640, and VVER -1500 (the last two designs are at various stages of development and have no references).

VVER reactors of first generation

The first domestic water-cooled water-moderated power reactor was put into operation in 1964 at Novo-Voronezh NPP. The first two power units of this NPP demonstrated technical reliability of industrial power sources on nuclear fuel and allowed to create a series of power units of the first generation. These were VVER-440 with V-179, V-230, VВ-270 reactor installations developed in 1966-1975. Now 11 VVER-440/230 are operated worldwide, and five power units of this type were decommissioned.

At that time there were no comprehensive international safety standards, and VVER designs of the first generation were developed in accordance with the general industrial norms. These reactors were intended for generation of electric power with high availability.

In the eighties the Russian design organizations started solving the problems of safety enhancement and modernization of VVER-440 of the first generation. Currently these problems are successfully fulfilled.

VVER reactors of second generation

The safety system of VVER-440 of the second generation was considerably improved and met the western requirements of quality assurance and safety protection of that time. The NPP with VVER-440/213 were constructed as modules, 2 power units in one reactor building. The design basis accident (DBA) defined a double-sided cross-section rupture of the main circulation pipeline. Besides, redundancy of the safety systems and their auxiliary systems was enhanced. The core emergency cooling system was designed with consideration of the new DBA.

VVER-440/213 reactors in operation

Country

NPP

Power unit

Year of putting into operation

Russia

Kola

3

1982

4

1984

Ukraine

Rovno

1

1980

2

1981

Hungary

Pacš

1

1983

2

1984

3

1986

4

1987

Slovakia

Bogunice V-2

1

1984

2

1985

Czechia

Dukovany

1

1985

2

1986

3

1986

4

1987

Finland

Loviisa

1

1977

2

1981

VVER-1000 light water reactors are more similar to the western PWR reactors as per their design characteristics and structure. Designing of V-187, V-302, and V-338 first models was completed in 1979.

V-320 model of VVER-1000 reactor was developed later and met the requirements to safety elaborated in 1982. The concept of defense in depthincluded redundancy, distinction, independence and application of the single failure principle for the safety systems. Today there are 15 power units with VVER-1000/320 in operation in Russia, Ukraine, and Bulgaria.

VVER reactors of third generation

At the end of the nineties on the basis of the NPP design with VVER-1000 development of reactors of the third generation was commenced. In 2004 the Board of Ministry of Russia for Atomic Energy reviewed the question «About development of NPP with power units of larger capacity and its place in realization of strategy of development of nuclear engineering of Russia». In this connection the decision was taken on expediency of commissioning of the NPP with VVER-1500 head power unit after 2012.

The designs of the third generation include VVER-640, VVER-1000, VBER-300 and VVER-1500. Design developments of the third generation of reactors are created in view of extremely achievable conformity to the existing requirements in the field of nuclear engineering safety. These designs incorporate to a greater extent the features of internal safety including use of natural factors and passive technical means.

About Russian nuclear power technologies

Competitiveness of offers of Atomstroyexport is explained by application of the state-of-the-art technologies and the newest developments of the Russian scientists and designers. All projects are carried out under the framework of the state program «Ecologically clean power» and correspond to the current international requirements and IAEA recommendations.

The Russian experts prefer an evolutionary way to develop designs, therefore the present-day plants are advanced, modernized variants of the already proved base designs. The reactor installations, turbines, generators are permanently improved.

In China at Tianwan NPP, for example, the Russian NPP-91 design was applied, which single unit includes the reactor installation with VVER-1000/428 reactor and the turbine of К-1000-60/3000 type with TVV-100002Y3 generator. The turbine is an improved one as per a number of parameters, and having 2 thousand tons weight and being 51 meters long it is 1.5 times lighter than the similar low speed turbines for nuclear plants of such capacity. The main features of the generator are increase of capacity up to 1065 MW and increase of efficiency. The advanced reactor installation of VVER-1000/428 type with the improved neutron-physical characteristics and increased efficiency of emergency protection has a four-channel structure of the safety systems and a number of devices and systems, which allow to consider this design as one of the most safe in the world.

For construction of the NPP in India NPP-92 design with the enhanced safety characteristics and improved technical and economic parameters was adopted. The same design was chosen as a result of the bidding process for construction of Belene NPP in Bulgaria.

The present-day Russian designs, NPP-91 and NPP-92 with VVER-1000 reactors as per the basic technical and economic indices do not yield to their main foreign competitors  to the power plants with AP-1000 reactors (Westinghouse) and EPR reactors (Areva NP).

Nowadays the Russian reactor of «3 +» new generation or NPP-2006 design is being promptly developed. This reactor as per its technical and economic characteristics will not yield to the offers of foreign competitors.

Russian reactors of third generation

Requirements to safety of nuclear power plants constantly grow, and the main condition of competitiveness in the world market of NPP construction is construction of an NPP with a reactor of the third generation. Such reactors are now offered by Atomstroyexport JSC to foreign customers.

The NPP with a reactor of the third generation means:

a standard design prepared for accelerated licensing;

reduced dates and cost of construction;

a simple and reliable design, error-tolerant against possible mistakes of an operator;

high plant load factor and operation life time up to 60 years;

high fuel burnup and low quantity of radioactive waste;

protection against failure with core melting;

minimal environment impact.

These requirements are fully met by the Russian power units with VVER-1000 (NPP-91 and NPP-92 designs) and VVER-640 reactors. NPP-91 design was applied in China where Atomstroyexport JSC completed construction in 2007 of the first phase of Tianwan NPP consisting of two power units with VVER-1000.

NPP-92 design is being realized in India at Kudankulam NPP (two power units with VVER-1000 reactor) and in Bulgaria at Belene NPP, also consisting of two power units with VVER-1000.

About third of the cost of the present-day nuclear power plants with reactors of the third generation makes construction of various safety systems. Safety of the reactor installations is provided by application of the system of barriers on a path of propagation of radioactivity; by the passive and active safety systems; the latest I&C systems; the approved design solutions, and use of the measures excluding mistakes of the personnel.